.TH std::min_element 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::min_element \- std::min_element

.SH Synopsis
   Defined in header <algorithm>
   template< class ForwardIt >
   ForwardIt min_element( ForwardIt first, ForwardIt last   \fB(1)\fP (constexpr since C++17)
   );
   template< class ExecutionPolicy, class ForwardIt >

   ForwardIt min_element( ExecutionPolicy&& policy,         \fB(2)\fP \fI(since C++17)\fP

                          ForwardIt first, ForwardIt last
   );
   template< class ForwardIt, class Compare >

   ForwardIt min_element( ForwardIt first, ForwardIt last,  \fB(3)\fP (constexpr since C++17)

                          Compare comp );
   template< class ExecutionPolicy, class ForwardIt, class
   Compare >

   ForwardIt min_element( ExecutionPolicy&& policy,         \fB(4)\fP \fI(since C++17)\fP
                          ForwardIt first, ForwardIt last,

                          Compare comp );

   Finds the smallest element in the range [first, last).

   1) Elements are compared using
   operator<
   \fI(until C++20)\fP
   std::less{}
   \fI(since C++20)\fP.
   3) Elements are compared using the comparison function comp.
   2,4) Same as (1,3), but executed according to policy.
   These overloads participate in overload resolution only if

   std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.        (until
                                                                             C++20)
   std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true. (since
                                                                             C++20)

.SH Parameters

   first, last - forward iterators defining the range to examine
   policy      - the execution policy to use. See execution policy for details.
                 comparison function object (i.e. an object that satisfies the
                 requirements of Compare) which returns true if the first argument is
                 less than the second.

                 The signature of the comparison function should be equivalent to the
                 following:

                 bool cmp(const Type1& a, const Type2& b);
   comp        -
                 While the signature does not need to have const&, the function must
                 not modify the objects passed to it and must be able to accept all
                 values of type (possibly const) Type1 and Type2 regardless of value
                 category (thus, Type1& is not allowed
                 , nor is Type1 unless for Type1 a move is equivalent to a copy
                 \fI(since C++11)\fP).
                 The types Type1 and Type2 must be such that an object of type
                 ForwardIt can be dereferenced and then implicitly converted to both of
                 them.
.SH Type requirements
   -
   ForwardIt must meet the requirements of LegacyForwardIterator.

.SH Return value

   Iterator to the smallest element in the range [first, last). If several elements in
   the range are equivalent to the smallest element, returns the iterator to the first
   such element. Returns last if the range is empty.

.SH Complexity

   Given \\(\\scriptsize N\\)N as std::distance(first, last):

   1,2) Exactly \\(\\scriptsize \\max(N-1,0)\\)max(N-1,0) comparisons using
   operator<
   \fI(until C++20)\fP
   std::less{}
   \fI(since C++20)\fP.
   3,4) Exactly \\(\\scriptsize \\max(N-1,0)\\)max(N-1,0) applications of the comparison
   function comp.

.SH Exceptions

   The overloads with a template parameter named ExecutionPolicy report errors as
   follows:

     * If execution of a function invoked as part of the algorithm throws an exception
       and ExecutionPolicy is one of the standard policies, std::terminate is called.
       For any other ExecutionPolicy, the behavior is implementation-defined.
     * If the algorithm fails to allocate memory, std::bad_alloc is thrown.

.SH Possible implementation

                             min_element \fB(1)\fP
   template<class ForwardIt>
   ForwardIt min_element(ForwardIt first, ForwardIt last)
   {
       if (first == last)
           return last;

       ForwardIt smallest = first;

       while (++first != last)
           if (*first < *smallest)
               smallest = first;

       return smallest;
   }
                             min_element \fB(3)\fP
   template<class ForwardIt, class Compare>
   ForwardIt min_element(ForwardIt first, ForwardIt last, Compare comp)
   {
       if (first == last)
           return last;

       ForwardIt smallest = first;

       while (++first != last)
           if (comp(*first, *smallest))
               smallest = first;

       return smallest;
   }

.SH Example


// Run this code

 #include <algorithm>
 #include <iostream>
 #include <vector>

 int main()
 {
     std::vector<int> v{3, 1, -4, 1, 5, 9};

     std::vector<int>::iterator result = std::min_element(v.begin(), v.end());
     std::cout << "min element has value " << *result << " and index ["
               << std::distance(v.begin(), result) << "]\\n";
 }

.SH Output:

 min element has value -4 and index [2]

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

      DR    Applied to            Behavior as published              Correct behavior
   LWG 212  C++98      the return value was not specified if       returns last in this
                       [first, last) is empty                      case
   LWG 2150 C++98      the iterator to the first non-greatest      corrected the return
                       element was returned                        value

.SH See also

   max_element         returns the largest element in a range
                       \fI(function template)\fP
   minmax_element      returns the smallest and the largest elements in a range
   \fI(C++11)\fP             \fI(function template)\fP
   min                 returns the smaller of the given values
                       \fI(function template)\fP
   ranges::min_element returns the smallest element in a range
   (C++20)             (niebloid)
